1. Field of the Invention
The present invention relates generally to self-propelled agricultural bale wagons and, more particularly, to bale wagons of the type adapted to pick up large crop material bales of different sizes and to form stacks of the bales.
2. Description of the Related Art
Present day crop harvesting practices include the formation of large bales of crop material, such as hay or other crops, which are dropped in the field. Bale wagons are used to pick up the bales from the field, form the bales into a composite stack on the bale wagon and subsequently discharge the entire stack into a storage area. It is known for such bale wagons to include a first table which receives bales from a bale loader or pick up device mounted on the bale wagon. The first table accumulates a predetermined number of bales with the bales being arranged in a row in a pattern determined by a computer on board the bale wagon. A second table receives the rows of bales from the first table and accumulates several such rows. This group of rows is commonly referred to as a “tier”. A third table or load bed then receives the tiers from the second table and accumulates these tiers to form a “stack” on the load bed. Once the stack has been accumulated on the load bed, it may be unloaded by pivoting the load bed 90 degrees and depositing the stack on the ground or other surface so that the first tier of bales which was accumulated on the second table is now the lowermost tier of the stack on the ground surface.
Current bale collecting systems on self-propelled bale wagons for large bales include a clamp that grasps the bale, lifts the bale, and deposits the bale on a first collecting table. Large bales can be formed in different sizes, such as, for example, bales that are three feet wide and bales that are four feet wide. When changing from collecting bales of one size to collecting bales of another size, known bale wagon systems require that the operator make manual adjustments to the bale wagon, such as changing the general spacing between the opposed clamp arms, and/or changing a cushioning bumper between the arms. For example, some bale wagons have a single rotational clamp arm that is actuated by a cylinder. The rotational arm rotates away from a rigid clamp arm in order to provide a large aperture to receive bales. By taking advantage of geometric relationships, only a short stroke of a cylinder is needed to actuate the mechanism. However, with this type of structure, changing from collecting bales of one size to collecting bales of another size requires the operator to adjust the overall width of the clamp by removing a hydraulic cylinder mount, pulling a pin and sliding the frame to the desired position for the new size bales to be collected. Then, the pin has to be reinserted, and the cylinder mount reconnected before bale pickup can be started. This is problematic if the operator inadvertently adjusts the mechanism incorrectly, or forgets to make a required adjustment. The time required for making the mechanical adjustments prolongs the time required to complete the pickup task.
Another type of pickup mechanism on a bale wagon engages the bales with a translational system, such as a simple, laterally sliding mechanism that extends and retracts to allow bales to enter the opening. While these mechanisms may be operable with bales of multiple widths, they cannot provide a wide aperture for bale entrance without providing an excessively long translational element for clamping the bales. For example, to provide a 6 foot wide opening for picking up 4 foot wide bales, the translational element must have a cylinder with 2 feet of extra travel. The extra length can result in increased weight, and can require extra structure, larger packaging and increased cycle time due to the extra stroke of the cylinder. Further, for the clamp to adjust down to 3 feet for small bales or lesser widths for transport, the length of the cylinder becomes prohibitively expensive.
What is needed in the art is a bale wagon system that can pick up bales of multiple sizes without the need for making manual adjustments to the mechanism.